This invention relates to antimony halide-organic phosphate ester complexes useful as catalysts in organic, cationic polymerization reactions.
The use of catalysts in organic chemistry is well-documented, such catalysts often being specific for one or a limited number of reactions. Antimony-containing acid catalysts have been previously described as useful in hydrocarbon conversion processes, as for example in U.S. Pat. No. 3,975,299.
U.S. Pat. No. 3,590,025 discloses SbF.sub.5 and, among other possibilities, fluorides and oxyfluorides of phosphorus as catalysts for the polymerization of tetrafluoroethylene.
The catalysts of U.S. Pat. No. 4,088,822 may contain Pd, P and O and optionally Sb for the simultaneous production of methacrylic acid and methacrylate or acrylic acid and an acrylate. The element Sb is only optionally present in the catalyst composition of patentee's invention, and, in addition, the reaction catalyzed is not a polymerization.
In none of the above catalyst patents does one find antimony halide-organic phosphate ester compositions.
A number of cations have been combined with phosphorus for catalytic purposes. U.S. Pat. Nos. 3,474,041 and 4,013,586 disclose vanadium, phosphorus, oxygen catalyst systems in the oxidation of hydrocarbons to dicarboxylic acid anhydrides. These compositions are not phosphate complexes.
Antimony compounds have been disclosed as a promoters for other catalysts; i.e., the antimony compounds enhance the activity of the primary catalyst. U.S. Pat. No. 4,003,920 discloses that maleic anhydride can be made by oxidation of unsaturated hydrocarbons in the presence of oxides of tungsten and phosphorus and a catalyst promotor which may, among many other possibilities, be an antimony compound. Patentee does not disclose catalysts useful in cationic polymerizations.
U.S. Pat. No. 3,707,582 discloses PCl.sub.3 or POCl.sub.3 as a promoter and SnCl.sub.4 as a catalyst in the polymerization of isobutene. Patentee states in col. 2, line 27, that SbCl.sub.5 is not a useful catalyst in his invention.
Antimony pentachloride-phosphate complexes of the type useful in the present invention have been previously disclosed in the following scientific writings: K. Burger and E. Fluck, Inorg. Nucl. Chem. Letters, 10, 171(1974), V. Gutmann and U. Mayer, Monatsh. Chem.,98, 294 (1967), and Von R.--A. Luber and A. Schmidt, Z. Anorg. Alleg. Chem. 428, 209 (1977). Various properties of the complexes are described but no uses are disclosed.
The present invention discloses cationic polymerization catalysts which are the reaction product of antimony pentahalides with organic phosphate esters.